Switch operating mechanism



y 3, 1947. l. w. PATERSON 2,420,441

SWITCH OPERATING MECHANISM Filed March 18, 1944 gm 4 MM Patented May 13, 1947 UNITED STATES PATENT OFFICE SWITCH OPERATING MECHANISM Ira W. Paterson, Milton, Mass, assignor to Allis- Chalmers Manufacturing Company, Milwaukee, Wis., a corporation of Delaware Application March 18, 1944, Serial No. 527,027

(Cl. ZOO-F82) 7 Claims.

This invention relates in general to circuit breakers and control therefor of the type in which gas under pressure is utilized to operate the circuit breaker and relates particularly to an improved fluid operated brake and apparatus for controlling the operation of the brake for arresting relative movement of the circuit breaker contacts.

In fluid operated electric switches Where the movable switch contact and its associated actuating means have an appreciable amount of inertia, the kinetic energy of the switch and actuating means must be dissipated when the switch contact reaches one or the other end position thereof. In prior art braking systems such energy has been absorbed by suitable sprin s or by frictional brakes. Such frictional brakin systems have applied a braking effort that is independent of the operating effort applied to the switch actuating means to operate the same. This is a disadvantage especially where the contact operating force is a variable quantity.

It is therefore an object of the present invention to provide a fluid operated switch with an improved fluid operated brake mechanism that will supply'a braking effort proportional to the oper ating effort of the fluid operated motor utilized for actuating the switch contact.

It isalso an object of the present invention to utilize the same source of fluid pressure that is available for operating a fluid operated switch contact, to also operate a fluid operated braking mechanism for stopping such switch contact and dissipating the kinetic energy thereof.

It is also an object of the present invention to provide in a fluid operated brake for a movable switch contact member, a fluid operated control that will immediately release the braking action upon energization of the operating means to again actuate the switch contact.

It is also an object of the present invention to provide a fluid motor, for actuating a switch contact, with a fluid operated brake mechanism that is actuated only after a predetermined contact operating movement of the fluid operated motor.

Objects and advantages other than those above set forth will be apparent from the following description when read in connection with the accompanying drawing, in which the single figure is a diagrammatic showing of a circuit breaker and control therefor embodying the present invention.

The present invention is shown as applied to a fluid operated circuit breaker of the gas blast type. As shown in the drawing, the circuit breaker consists essentially of a fixed arcing contact 6 and a movable contact I connected in series with disconnect contacts 8 and 9 in a circuit indicated by conductors I l. The movable arcing contact I is actuated to open position by the breaking of a toggle formed by links 9|, one end of which is anchoredto the circuit breaker frame by a spider member 99. The toggle 9| is broken by movement of piston 92 to the right as viewed in the drawing. The piston 92 is biased by spring 93 to hold the arcing contacts 6, l in the closed position shown. The toggle 9| is electrically paralleled by shunt 13.

When the arcing contacts 6, 1 are separated,

the are drawn therebetween is blasted through the orifice 28 against auxiliary contact 95, thereby connecting the resistance in circuit with the arc. The effect of the resistance 96 and the deionization and cooling provided by the blast of air through the Orifice 28, quickly eXtinguishes the arc and interrupts the circuit through conductors I 1. After the are is extinguished at the arcing contacts 6, l, the disconnect contacts 8, 9 are opened thereby isolating the conductors H. The movable disconnect contact 9 has its opening and closing movement arrested by an improved fluid operated and controlled braking mechanism. Opening of the disconnect contact 9 effects closure of the blast valve 14, thereby permitting the spring 93 to reclose the arcing contacts 6, l. The circuit is closed by closing the disconnect contacts 8, 9.

Separate fluid operated motors l2 and [3 are provided for closing and opening actuation, respectively, and these motors are interlocked with each other and with the blast valve operation to provide for rapid operation, especially when the breaker is closed and immediately reopened or opened and immediately reclosed. In high voltage circuit breakers of the type used for outdoor installations, the disconnect contact 9 and its operating members are necessarily large and heavy and therefore have great inertia. These members are not only rapidly operated, but also provision is made for absorbing their kinetic energy and for preparing for an immediate reverse operation.

The circuit breaker is shown with all parts thereof and of the pneumatic control system in the open circuit position. A closing operation is initiated by energization of the closing solenoid valve 34, thereby permitting air under pressure from tank I! and feed pipe 21 to be fed to pipe 71. Air under pressure in pipe 11 acts through pipe H on the slide valve 68 of the opening motor I3. A slot 12 in the operating link of slide valve 68 permits the slide valve 68 to be moved to the left, thereby opening port 69 in cylinder 62 to atmosphere through port 19. This permits bleeding to atmosphere of any air under pressure in cylinder 62 of opening motor l3 tending to provide an opening impulse.

Pressure air in pipe 11 also opens check valve ?8 against the bias of its spring 99 and feeds air under pressure to the cylinder 19 through the passage i9. Opening of check valve 18 closes the port 89 and the passage through the needle valve 8|, so that the air presssure in cylinder 15 is available for movement of piston 15. This air pressure moves piston 15 to the left, rotating shaft Hi to close the movable disconnect contact 9. The impact of stopping the closing movement of contact 9 is cushioned by action of opening piston El in opening cylinder 62. As closing movement of the contact 9 takes place, a pin on the operating link 53 moves in the slot 12 of the slide valve 68 and further movement of shaft and link 53 moves the slide valve 68 to the right as viewed in the drawing, thereby closing port 19. Further movement of the piston BI is utilized to cushion the impact of stopping the closing mechanism by compressing the remaining air in cylinder 62 to a degree adjusted by the amount of air bled through the passage 65 past the needle valve 61.

In the present invention, a frictional braking of the disconnect operating mechanism is utilized, and the braking effort is controlled pneumatically and is proportional to the operating force applied by the contact actuating motors. As the closing piston 15 is moved a predetermined dis tance to the left as viewed in the drawing, a port G2 in the wall of cylinder 16 is uncovered. This places air under a pressure proportional to the pressure in cylinder 75 in the feed pipe 43.

This air pressure is fed through check valve 44 and adjusting valve 45 to the passage 46 and as check valve 55 and port 51 are closed, this pressure is transmitted through distributing pipe 41 to the brake at each pole of the breaker. The brake is shown as comprising brake shoes 31 provided with a brake lining 38 acting on a drum 36 connected to shaft I9. When air under pressure in pipe 4'! is fed underneath piston 39 in brake cylinder 49, the brake shoes 31 are tightened about the drum 3%, arresting movement of shaft It.

Inasmuch as the pressure in tank I! is a variable quantity and it is desirable to have the disconnect stopped at a predetermined position independent of the tank pressure, the braking effort is in the above manner, made proportional to the tank pressure.

Closing movement of the shaft Ii) also moves link 33 to reset the operating mechanism of the blast valve I 4 for an opening operation. Closing movement of the shaft [9 moves slide valve 22 to the right as viewed in the drawing, closing the ports 2 and This closes the space above pistons l8 and 2% of the main and pilot valves i4 and 15 in readiness for an opening operation. Movement of link 33 also moves slide valve 26 to the left as viewed in the drawing closing the air passage and opening the space underneath piston is to atmosphere through passage 25 and port 3|. The valve operating mechanism is now ready for an opening operation. Slide valve 82 is moved by a pin on the operating link 63 acting in the slot M to open ports 33 and 84. This bleeds the slot 14.

out air behind the closing piston 15 and prepares closing motor [2 for proper functioning during an opening operation. The breaker is now closed.

To open the breaker, solenoid valve 35 is energized placing pressure air from pipe 21 on top of piston 29 of the pilot valve l5. Opening of the pilot valve l5 places pressure air from pipe 2'! on top of piston l8 of the main blast valve Id. The pipe 21, the opening controlled by valve l5 and the passageway from the valve to the piston If; all have relatively large cross-sectional areas so that opening of the blast valve takes place immediately upon opening of the pilot valve 15. Opening of the blast valve l4 places pressure air in the manifold I6 and also in the chamber containing the arcing contacts 6, 1.

While the pressure is being built up in the contact chamber, substantially full contact pressure is maintained on the arcing contacts until separation actually begins, due to the action of spring 93 and toggle links 9!. Pressure from the contact chamber acts through valve 94 upon piston 92 to break the toggle 9|, thereby separating the arcing contacts. The needle valve 94 is adjusted to assure opening of the arcing contacts only after there is a predetermined air pressure in the contact chamber. The are formed at the separating arcing contacts 6, I is then extinguished by the blast of air in the manner previously described.

The disconnect contact 9 is opened a predetermined time after opening of the arcing contacts. Air from the blast tube I6 flows through the feed pipes 64 and 83 and acts on piston 81, raising the same until the projection 89 is stopped against the check valve 18 holding the same closed. In this position of piston 31, the pipe 88 is opened to atmosphere through pipe 59 and port 58. The diameter of piston 81 is greater than that of valve 18. Thus, the action of piston 8'! not only prevents closing air from opening the check valve 18 and being applied to the piston IE, but also bleeds off any closing air pressure retained in the pipe H which might be available to initiate a closing operation even though the valve 34 is not opened. This interlock is especially advantageous on a close-open operation, where opening takes place immediately after closure.

The air bled to atmosphere through pipes 86 and 59 by movement of piston 87 moves the slide valve of the brake control against the bias of its spring 56, thereby opening the port 51. This bleeds to atmosphere any air under pressure in passage 46 and pipe 41, thereby releasing the brake shoes 3'! by action of spring 41. This is especially important on a close-open operation. This interlocking control maintains the disconnect contact in the closed position until opening air pressure is actually available in feed pipe 64.

Air under pressure in feed pipe 64 is also fed through pipe 85 to the slide valve 82. This action maintains the ports 83 and 84 open until the pin on member 93 has moved to the end of The closing motor is thereby prevented from arresting the action of the opening motor during the first part of its opening stroke. Pressure air from the blast tube 15 is also fed. through pipe 64 to check valve 65 of opening motor 13. Movement of check valve 65 closes the port 66 and permits pressure air to build up in cylinder 62, thereby moving piston 61 to the left and opening disconnect contact 9.

When piston SI has moved a predetermined distance of its contact opening movement, port 48 is uncovered and air under pressure proportional to the air pressure in cylinder 62 is fed through pipe 49, check valve 50, valve 5|, passage 46 and pipe 41 to operate the brake shoes 31 in a manner similar to the operation when closing contact 9.

In order to conserve blast air and to rapidly prepare the operating system for immediate reclosing of the disconnect contacts, opening movement of the shaft I0 acting through link 33 moves the slide valve 22 to the left as viewed in the drawing, first opening port 30 to permit pressure air from above piston to discharge to atmosphere through the port 23. This permits pilot valve 15 to be immediately closed by action of its biasing spring 2|. Further movement of slide valve 22 to the left opens port 24 permitting air above the piston [8 of the main blast valve to be exhausted to atmosphere through port 23.. To aid in rapidly resetting the blast valve 14, opening movement of the shaft l0 and link 33 moves slide valve 26 to the right closing the port 3| and opening the port 32 so that pressure air is applied through passageway to the underside of the piston Hi. This aids the spring Hi to rapidly close the blast valve l4, thereby conserving the air pressure in tank I1 and resetting the blast valve for an opening operation.

During the opening movement of the shaft in, slide valve 82 is moved to the right when the pin on link 63 moves to the end of slot 14 and slide valve 82 therefore provides for the cushioning action of piston 15 in the same manner as described with regard to the action of piston BI and the slide valve 68 during the closing operation. The cushioning action of piston 15 is regulated by the needle valve 8|.

Only one pole of the circuit breaker has been referred to in describing the general operation,

however the blast tube l6 and the operating link 98 on shaft l0 may extend to the other poles of the breaker and operate the contacts thereof at the same time.

Solenoid valves 34 and 35 are placed close to the main stop valve 29 so that operation or partial operation can not occur when valve 29 is shut because of air stored in the pipes between valves 34 or 35 and valve 29.

Selective adjustment of the braking effort supplied to stop the opening and the closing actution is provided by valves and 5|. It is usually desirable to provide different braking efforts when closing and when opening. Check valves 44 and are placed immediately adjacent the passage 46, so as not to impair adjustment of either valve by the reservoir action of the feed pipes.

Although but one embodiment of the present invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. An electric switch comprising a pair of relatively movable cooperating contacts, fluid operated motor means for relatively moving said contacts, means for supplying fluid under pressure to said fluid operated motor, a fluid operated brake mechanism of the frictional type for arresting the relative movement of said contacts, and means for supplying said fluid under pressure to said brake mechanism at substantially the same pressure.

2. An electric switch comprising a pair of relatively movable cooperating contacts, fluid oper ated motor means for relatively moving said contacts, means for supplying fluid under pressure to said fluid operated motor, a brake mechanism of the frictional type for arresting the relative movement of said contacts, and means for actuating said brake mechanism to supply a braking effort proportional to the operating effort of said fluid motor.

3. In an electric switch, a pair of cooperating contacts, a fluid operated motor for opening and closing said contacts, means for supplying fluid under pressure to said fluid operated motor, a fluid operated brake mechanism for arresting movement of said contacts, and means for supplying said fluid under substantially the same pressure to said brake mechanism after a predetermined contact operating movement of said fluid motor.

4. In an electric switch, a pair of cooperating contacts, a fluid operated motor for opening said contacts, a fluid operated motor for closing said contacts, a fluid operated brake mechanism for arresting said contact movement, means for selectively supplying fluid under pressure from said fluid motors to said brake mechanism, and valve means for relieving pressure supplied to said brake mechanism upon operation of one of said fluid motors when the other of said fluid motors is o-peratively energized.

5. In an electric switch, a pair of cooperating contacts, a fluid operated motor for opening said contacts, a fluid operated motor for closing said contacts, a fluid operated brake mechanism for arresting said contact movement, means for selectively supplying fluid under pressure from said fluid motors to said brake mechanism, and means for selectively adjusting the rates of flow of fluid under pressure from said fluid motors to said brake mechanism.

6. In an electric switch, a pair of cooperating contacts, a fluid operated motor for opening said contacts, a fluid operated motor for closing said contacts, a fluid operated brake mechanism for arresting said contact movement, means for selectively supplying fluid under pressure from said fluid motors to said brake mechanism, means operable upon energizing said contact opening motor for preventing energization of said contact closing motor and for relieving fluid pressure in said contact opening fluid motor, and means including said last said means for relieving said fluid pressure supplied to said brake mechanism.

'7. An electric switch comprising a pair of relatively movable cooperating contacts, fluid operated motor means for relatively moving said contacts, means for supplying fluid under pressure to said fluid operated motor, a fluid operated brake mechanism of the frictional type for arresting the relative movement of said contacts, and means for supplying to said brake mechanism a fluid under pressure proportional to the pressure of said operating motor fluid.

IRA W. PATERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,180,677 Haller Nov. 21, 1939 2,310,755 Thumim Feb. 9, 1943 2,023,597 Klocke et a1. Dec. 10, 1935 2,281,337 Stegelitz et a1 Apr. 28, 1942 

